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Combined use of contemporary radiological modalities, particularly integration of structural, metabolic, and functional imaging, provides optimal multifaceted information for detailed characterization of intracranial gliomas. It allows differentiation of the tumor from non-neoplastic pathology, its non-invasive histopathological typing and grading, prediction of patient prognosis and clinical course of the disease, detailed planning of surgical resection or biopsy, critical postoperative assessment of the residual lesion, effective surveillance during follow-up with evaluation of effectiveness of the adjuvant therapy and timely identification of recurrence, and even insights into molecular signatures of the neoplasms. Therefore, advanced neuroimaging is one of the most important cornerstones of the modern neuro-oncology., (© 2018 S. Karger AG, Basel.)

Background/aims: The objective of the present study was the evaluation of the effectiveness of robotic microradiosurgery of skull base meningiomas using Leksell Gamma Knife model C with an automatic positioning system., Methods: The results of the management of 66 tumors were analyzed retrospectively. Their volume varied from 0.3 to 50.6 cm³ (mean = 6.6). The treatment plan was based on the use of multiple small isocenters compactly positioned within the border of the lesion with resultant improved homogeneity of high-dose distribution, increased average dose within the target and sharp dose fall outside the treated volume. The marginal dose varied from 10 to 14 Gy (mean = 12). The length of follow-up ranged from 26 to 80 months (mean = 46)., Results: The overall tumor growth control was 99%. Reduction of the mass volume was marked in 54 patients (82%), and in 15 of them it constituted ≥ 50%. In other 11 cases (17%) stabilization of the lesion growth was noted. The shrinkage rate significantly correlated with amount of radiation energy delivered per tumor volume, designated as unit energy (p = 0.007). One meningioma (1%) regrew 3.5 years after radiosurgery. The treatment-related morbidity was limited to transient abducens nerve palsy in 1 patient (1%)., Conclusion: Application of the concept of Gamma Knife robotic microradiosurgery for the management of skull base meningiomas may change the paradigm of their treatment from stabilization of growth to reduction of the volume of the neoplasm. The tumor shrinkage rate may depend on the amount of radiation energy delivered per lesion volume (unit energy)., (Copyright © 2010 S. Karger AG, Basel.)

Background/aims: The present study analyzed the initial experience with the application of the original concept of 'robotic microradiosurgery' using Leksell Gamma Knife Model C with automatic positioning system for management of craniopharyngiomas., Methods: Eighteen patients with residual or recurrent craniopharyngiomas underwent radiosurgery with the use of multiple isocenters, mainly of smaller size, which were positioned compactly within the border of the lesion with resultant improved dose homogeneity, increased average dose within the target, and sharp dose fall outside the treated volume. Treatment planning was mainly guided by constructive interference in steady state images with and without gadolinium enhancement. Mean tumor volume was 1.8 cm(3). In 12 cases the anterior visual pathways were either compressed or attached to the lesion. The average number of isocenters was 8.7 per cubic centimeter of target volume. Mean marginal irradiation dose was 11.6 Gy. Mean maximal dose to the anterior visual pathways was 8.4 Gy. Mean follow-up was 26.8 months, and median follow-up was 24 months., Results: Tumor growth was controlled in 17 cases (94%), and its volume reduction was attained in 13 cases (72%). In 3 patients significant shrinkage of the neoplasm after radiosurgery was accompanied by improvement of the visual functions. Their impairment was not marked in any case, nor was there any new endocrinopathy., Conclusion: Application of robotic microradiosurgery to the management of residual and recurrent craniopharyngiomas showed promising results during short- to intermediate-term follow-up, providing early tumor shrinkage in the majority of cases as well as sparing of visual and pituitary functions., ((c) 2009 S. Karger AG, Basel.)

Background/aims: To identify the pyramidal tract by neuronavigation based on intraoperative diffusion-weighted imaging (iDWI) combined with subcortical stimulation., Methods: Seven patients with brain tumors near the deep white matter underwent resection surgery using neuronavigation based on iDWI to visualize white matter bundles. Subcortical electrical stimulation was performed and electromyography was measured at the extremities when surgical manipulation came near the position corresponding to the depicted bundle. We validated the bundle depicted on iDWI by considering the responses to subcortical stimulation and the distance between the stimulation site and the depicted bundle., Results: Positive motor-evoked potentials were detected in 5 of 7 patients (8 stimulations) and the distance from the stimulation site to the depicted bundle was 0-4.7 mm (mean +/- SD, 1.4 +/- 2.1 mm). Negative (no) responses were obtained in all patients when the distance was more than 5 mm. The neuronavigation system had an average error of 0.79 +/- 0.25 mm and a maximum error of 2.0 mm (n = 16)., Conclusion: Neuronavigation based on iDWI combined with subcortical stimulation allowed surgeons to identify the pyramidal tract and avoid inadvertent injury. Our findings demonstrate that the white matter bundles depicted by iDWI can contain the pyramidal tract.

Mislocalization errors caused by MR image distortions or brain shift are one of the main causes of complications after stereotactically guided neurosurgical procedures. A special device, which could ameliorate such effects and provide intraoperative acquisition of MR images of sufficient diagnostic accuracy, was developed. It is composed of a radiofrequency receiver coil integrated with a modified Komai stereotactic frame and a Sugita four-pin head holder. Clinical testing revealed that the use of the device during stereotactically guided procedures under the control of low magnetic field strength (0.3 T) intraoperative MRI ameliorates the effects of brain shift, and permits to obtain informative tissue samples and to perform aggressive removal of the lesion without any damage of the eloquent cerebral structures. The possibility of an easy shift from a stereotactically guided to a routine microneurosurgical procedure represents an additional benefit of the developed device., (Copyright 2006 S. Karger AG, Basel.)

Information-guided stereotaxis, assisted by visualization of medical information, will become the next generation of neurosurgical systems. We performed 76 open MRI surgeries at Tokyo Women's Medical University between March 3, 2000 and April 12, 2001. Of them, comparisons of pre- and post-operative MR images for malignant gliomas in 21 cases revealed an average resection rate of 90.3% (the maximum 100%, the minimum 55%). In this article we describe real time updated navigation, augmented reality navigation, three-dimensional navigation, chemical navigation, information-guided navigation system (High definition visual Computer Aided Surgery System: HivisCAS), and open MRI-guided surgery that we are developing., (Copyright 2002 S. Karger AG, Basel)

Objective: We have developed an overlaid three-dimensional image (Volumegraph)-guided navigation system that allows navigation during operative procedures. The three-dimensional image is superimposed on the patient's head and body via a semi-transparent mirror. The Volumegraph can display three-dimensional images in the air by a light beam which is based on CT/MRI., Method: The system consists of a Volumegraph (thin plate of three-dimensional recorded medium), a Volumegraphscope and an original designed triangular-shaped marker system for registration. The three-dimensional data obtained from CT and MRI before the operation were processed by a computer. Such image data are applied for preoperative investigation to recognize the three-dimensional structure of organs and tumor. These reconstructed three-dimensional images were superimposed and registered at the patient's head according to a fiducial marker (registration). Then the operator can operate with this three-dimensional-image-guided navigation system., Results: Based on clinical application in 7 cases, the system was found to be advantageous because the surgical procedures could be navigated easily by augmented reality in the surgical field. Invisible parts of the surgical field were supplemented with the overlaid three-dimensional images (Volumegraph) as if it were the virtual operative field. At another time, spatial positioning and overlaid visualization by the Volumegraph was useful for identifying anatomical structures and functional location in the image., Conclusion: This preliminary study of overlaid three-dimensional-image-guided navigation demonstrated its clinical usefulness. The application of augmented reality in the surgical field makes it possible to do a neurosurgical intervention easily and accurately.

We examined whether lymphatic metastasis was inhibited by the potent angiogenesis inhibitor AGM-1470 [O-(chloroacetyl-carbamoyl)fumagillol, TNP-470] using a rat lymphatic metastasis model. Clone A of the rat fibrosarcoma AS653HM, when inoculated into the footpads of syngeneic rats, highly and preferentially metastasized to lymph nodes. In contrast, when AGM-1470 was administered subcutaneously to rats bearing the tumor cells, the tumor growth and incidence of metastasis in the lymph nodes were reduced in a dose- and schedule-dependent manner. Similar inhibition of lymphatic metastasis was also observed in the rats in which treatment with AGM-1470 was initiated following resection of the primary tumor in the foot, indicating that the treatment with AGM-1470 inhibited the progression of lymphatic metastasis at the metastatic sites of the lymph nodes. These results suggest that AGM-1470 can be a potential agent to prevent lymphatic metastasis.

Baclofen, an agonist of the gamma-aminobutyric acid (GABA) receptor, has antinociceptive effects, and its intrathecal administration reduces allodynic responses in animal models of neurogenic central pain. Such experimental studies lead to the hypothesis that neurogenic pain may be induced in part by functional abnormalities in spinal GABAergic systems. However, whether a GABAergic system is actually involved in human central pain is unknown. The authors investigated the effect of an intrathecal bolus injection of baclofen in 14 patients with central pain due to a stroke or spinal cord injury. Nine reported substantial pain relief they had never experienced previously. The effect appeared 1-2 h after the injection and persisted for 10-24 h. Allodynia and hyperalgesia, if present, were relieved as well. Pinprick and light touch sensations did not change in nonaffected regions. The results indicate that dysfunction of spinal GABAergic systems plays a role in the clinical expression of central pain. In clinical situations, continuous intrathecal infusion of baclofen seems feasible for relief of central pain.

A new simulation system utilizing digital images (CT/MRI/SPECT) and an ultrasound/laser navigation system has been developed for image-guided surgery. Preoperative CT/MRI imaging does not always indicate the actual location of the lesion during intracranial operation, because the lesion may be displaced or distorted by operative procedures or CSF flowout. The authors developed an image integration system including an intraoperative ultrasonogram, which provides accurate information not only on the location of the deep-seated lesions but also surrounding anatomical structures during operation. The rationale of the system is to coordinate the three-dimensional axes of each image with the aid of a stereotactic subframe. Our simulation system has two ways. One simulation system works on a SUN workstation. At the preoperative simulation study: the entry point on the brain surface and the access route to the lesion are decided on from the three-dimensional CT/MRI images on the computer display. Then the configuration of the lesion from the operative view is displayed as an expected ultrasound image by reconstructing the CT and/or SPECT image. Another simulation system (HyperCAS) works on the HyperCard of a MacIntosh. The target point, the entry point and the trajectory are decided on and the three-dimensional location of these points is measured from serial CT images on the LCD display. At the time of operation, stereotactic craniotomy is performed using the laser navigator. The extent of the lesion at every depth in the surgical process is predicted from these images, and the access route to the lesion is easily corrected with the intraoperative ultrasound navigator.(ABSTRACT TRUNCATED AT 250 WORDS)

Stereotactic volumetric resection of deep-seated intracerebral lesions is generally believed to require expensive and complex facilities. The authors report a simple system for stereotactic craniotomy, in which the software in the computed tomographic scanner and a personal computer are used for preoperative planning and intraoperative orientation.

Rostral mesencephalic reticulotomy (RMR) for pain relief was performed in 34 patients with intractable pain. Most of these patients have been followed for a long period of time postoperatively, the longest follow-up period being 11 years. Contrary to the commonly prevailed bias in the past that mesencephalotomy may be a surgical intervention with potential risk, these patients of RMR have continued to substantial improvement postoperatively in terms of their preoperative intractable painful dysesthesia after a long period of time. The results of pain relief for denervation pain as well as for nondenervation pain are surprisingly good even after unilateral procedures. There was no operative mortality. Postoperative disturbance of ocular motility has been reduced. RMR has its scientific basis in that the medial part of the reticular formation rather than the classical lateral spinothalamic tract has more significance in the central conduction of nociceptive impulses through the midbrain level, which was verified by intraoperative neuronal recording with a tungsten microelectrode. The present report emphasizes that stereotactic mesencephalotomy, if performed meticulously and precisely, is a safe surgical procedure for pain relief. Results of MRI and sensory manifestations of a patient 11 years after RMR are also presented.

A long-term follow-up study of rostral mesencephalic reticulotomy (RMR) for pain relief is presented. 34 patients (24 males and 10 females) were operated. Ages ranged from 18 to 65 years. The follow-up period was 1-70 months. The overall effectiveness of RMR showed good relief of pain in 23 patients (67%). The study of effectiveness of RMR according to type of pain showed good relief of pain in 5 out of 6 patients (83%) with nondenervation pain, whereas satisfactory pain relief was obtained in 18 out of 28 patients (64%) with denervation pain.

Rostral mesencephalic reticulotomy (RMR) has been performed since 1973 for relief of intractable pain. The target area is in the midbrain reticular formation (MRF) bordering the periaqueductal gray matter at the superior collicular level. The target of RMR is 13--16 mm posterior to the midpoint of the AC-PC line and 5--8 mm below the AC-PC line. The laterality of the target is measured from the center of the aqueduct, ranging 5 to 8 mm from the midline. The rationale for this procedure is based upon the previous findings that the brain stem reticular formation plays a more important role above the spinal cord level than the lateral spinothalamic tract in the central conduction of nociceptive impulse. In the present study, intraoperative single neuron recording was made with tungsten microelectrodes from the human midbrain tegmentum in response to peripheral pinprick stimulation. These nociceptive neurons were classified into three groups in regard to the unit latency from the peripheral pinprick stimulation.

As a new clinical approach for the purpose of mapping a lamina analysis, the present report deals with another landmark for insertion of the spinal needle in man other than the usual dentate ligament when performing a percutaneous cordotomy. Electrophysiological studies were made on 19 patients in order to determine the effect of electrostimulation with a bipolar concentric electrode, as well as to corroborate the position of the electrode radiologically. A new apparatus has been devised so that one can locate the target insertion point easily.

During the last 3 years, 46 cases of hypertensive intracerebral hemorrhage were treated by CT-guided stereotactic surgery. Our present report is concerned with the evaluation of this procedure in the treatment of hypertensive intracerebral hematoma, in terms of the rate of aspirated hematoma and follow-up study of patients. It is difficult to draw any definite conclusion about the operative indications. CT-guided stereotactic aspiration, however, can be evaluated as a less invasive and more definitive treatment of intracerebral hematoma in the basal ganglia and thalamus.

67 cases of various functional disorders of the diencephalon were examined by EMI scanner. The patients were composed of 38 cases of parkinsonism, 7 cases of thalamic syndrome, 6 cases of choreoathetoid movement, 2 cases of dystonia, 11 cases of involuntary movement of unknown etiology and 1 case of torticollis, tic, and ballismus, respectively. In parkinsonism, 79% showed diffuse cerebral atrophy, 5% had focal low density in the substantia nigra and the thalamus, whereas 16% remained normal. Pre- and postoperative assessment with CT scan was briefly discussed with reference to stereotactic surgery of the diencephalon.

Immunoreactive beta-endorphin in the third ventricular fluid was measured in response to electrical stimulation of the periaqueductal gray matter in 8 patients with intractable pain during rostral mesencephalic reticulotomy for pain relief. In all patients, marked increase of immunoreactive beta-endorphin was observed. On the other hand, in cases of electrical stimulation of the zona incerta performed during stereoencephalotomy, in 5 patients with involuntary movement, immunoreactive beta-endorphin in the third ventricular fluid did not show any significant change. The authors conclude that the increase of immunoreactive beta-endorphin on electrical stimulation of the periaqueductal gray matter is not a nonspecific response to brain stimulation but a specific response in regard to cerebral localization of endorphins. Direct correlation between pain relief and periaqueductal gray stimulation is also questioned.

Combining whole-body CT scan with a stereotactic system, the authors have developed and applied clinically an apparatus which readily provides intraoperative CT images, making it possible to confirm the location of the target point and ascertain the intraoperative environment. It takes about 9 s to obtain a CT image. Our purpose is to make stereotactic surgery, a kind of blind surgery, as safe and reliable as a visualized procedure by intraoperative CT scanning. By the method, in which there is very little invasion under local anesthesia, evacuation of deep-seated intracerebral hematomas as well as brain abscesses and also biopsy or brachytherapy of brain tumors in the brain can be done with safety and reliability.